Battery-gage.



No. 686,56l. Patented No'v. I2, |90I.

C. R. UNDERHILL.

BATTERY GAGE.

(Application led Feb. 19, 1901.)

(No Model.)

@#,mf/MQM UNITE-D STATESv PATENT OFFICE.

CHARLES R. UNDERHILL, OF MONTCLAIR, NEW JERSEY, ASSIGNOR OF ONE- HALF TO THE VARLEY DUPLEX MAGNET COMPANY, OF JERSEY CITY, NEW JERSEY,`A 'CORPORATION OF NEW JERSEY. i

BATTERY-GAGE.

SPECIFICATION forming part of Letters-*Patent No. 686,561, dated November 12, 1901.

Application Bled February 19, 1901. Serial No. 47,928. (No model.)

T @ZZ wwiw il? may COW/GWW to a binding-post 25, mounted on the edge of 5o Beit known that LCHARLES RUNDERHILL, the case near one side of the pendant andina citizen of the United`Sta'tes,residingin Montsulated therefrom by a suitable non-conduct clair, in the county of Essex and State of New ing bushing 26. The other terminal 27 of Jersey, have invented certain new and useful the magnet-coil is connected to one end of a Improvements in Battery-Gages, of which the resistance, preferably in the form of a coil 55 following is a specication. or spool of insulated wire 28, mounted in some This invention relates to battery-gages, and suitable manner near the opposite side of the more particularly to the provision of a small case-as, for example, upon a bracket 29, se-

Io compact instrument which may be easily carcured to one of the heads of the spool and to ried in the pocket, by which the current the case. The other terminal 30 of the re- 6o strength, electromotive force, and internal resistance-coil is shown as having metallic consistance of an electric battery or like source tact with. the inside of the case, to which it of electrical energy may be readily deter-1 may be soldered or otherwise connected at mined with considerable accuracy. 31, permitting any current passing to iow to In the accompanying drawings, Figure 1 is the binding-post 32, which is conveniently 65 a front elevation of onel embodiment of my mounted upon the edge of the case at the opinvention. Fig. 2 is a rear elevation thereof posite side of the pendant from the post 25 with the wall ofthe caseremoved. Fig. 3 is and is electrically connected with the case.

zo a side elevation with a portion of the case vWithsome point in the conductor between broken away, and Figli is a detail in elevathe magnet-coil and the resistance-coil is 7o tion, parts being broken away, showing the yconnected a conductor 32, which leads to manner of attachment of certain parts to a `one point of contact of a switch or cut-out,

- pivot-pin. (designated as a whole by 33,) which con- Similar characters designate like parts tactis shown as a post or pin 34, supported throughout the several views of the drawings. `upon the plate 16 and insulated therefrom .by 75 The numeral 10 designates as a whole a suitable non-conducting material 35. With suitable inclosing and supporting case for the 'this' contact-post coacts the movable menivarious elements of the gage, which is here ber of the cut-out, here shown as a strip 36,

3o shown in the convenient form o f awatch proof spring sheet metal, secured to a stud 37 vided with a removable ,back 11, a tra'nsat one end and free at the other, Vstanding 8o parent front or crystal 12, and the usual normally away from the post 34. The stud Watch-case pendant 13, upon which turns the 36 may be directly connected to the binding- `fluted knob 14 and to which is attached a post 32 byaconductor 38. Through an open- 3 5 ring 15 for convenience in handling or for coning in the edge of the case projects a fingernecting to a guard-chain. Within the case piece for operating the cut-out, which iin- 85 is supported aplate 16, of some non-magnetic 'ger-piece may be attached to the strip 36. material, which carries upon the outer side When pressed, this finger-piece serves to under the crystal the face or dial 17, which move the spring member into contact with 4o may conveniently be of pasteboard, having the other member of the cut-out, and thereby inscribed upon it a suitably-graduated scale into connection withtheconductor32, thus 9o 18, here shown as divided into spaces readplacing the binding-post 32 in direct connecing in amperes -and quarters thereof. Upon tion with the magnet-coil through a low rethe opposite side of the plate is mounted near sistance and cutting the resistance-coil out one side of the case an electromagnet 19, comof the circuit. Extending through an openprising a coil 20, and suitable pole-pieces 2l ing in the plate and turning therein is a pivot 9 5 22 upon its central core, with a non-magnetic or pin 4:1, which may be formed at its inner strip 23 between said pole-pieces. One of the end with a head 42 and threaded at 42' for a terminals 24 of this magnet-coil is connected portion of its length. Threaded upon this portion with one face resting against the plate is a gear 43, and at the outside of the plate the pivot carries a nut 44, resting in a recess in the dial, the gear and nut tending to retain the pivot against longitudinal movement through the plate. To a reduced portion 45 at the outer end of the pivot is secured a needle or pointer 46 with its end moving over the scale. Operating in connection with the electromagnet is an armature 47, preferably of sufficient length to extend between its pole-pieces and prevented from adhering thereto through residual magnetism by the strip 23. This armature is shown attached to one end of a coiled spring 47', the opposite end of which spring is clamped between t-he head of the screw-pin 41 and theinner face of the gear 43. The armature and needle are so situated in relation to one another that when the former is resting against the strip 23 upon the pole-pieces of the magnet with its supporting-spring free from tension the latter will stand at zero on the scale. Secured to the armature at the opposite side from the magnet is a disk or indicator 48, so located that in certain positions of the armature it will appear at an opening 49 through the plate 16 and face. A stop 49 is secured to the plate, extending into proximity with the opening and into the path of the armature, serving to prevent the indicator from moving by the opening.

Secured to and turning with the stem of the knob 14 is a pinion 50, meshing with the gear 43 to impart rotation to it. To limit the arc through which rotation may occur, thus preventing the needle from being moved off the scale, a segment of the gear is cut away at 5l, and a stop 52, secured to the plate 16, extends into the opening. Upon the inner face of the gear presses a spring braking-finger or retainer 53, secured to the plate by screw 54 and having passing through it a screw 55,by which its tension may be adjusted.

In manufacture the instrument is provided with a magnet-coil of known resistance-for example, tive ohms-and a resistance-coil of known resistance, which may also conveniently be iive ohms. The face is then properly calibrated in amperes by comparison with a standard ammeter.

In use the gage is connected through the binding-post by suitable conductors from the terminals of the battery or other source of electrical energy which it is desired to measure. The current will then flow through the magnet-coil, the resistance-coil, and the body of the case, the two coils being in series, the entire current in the circuit owing through both. The armature will be attracted to the magnet and held with a certain force proportional to the current strength passing in the circuit. The iiuted knob, which serves as a rotary finger-piece, is then slowly turned to move the needle from zero over the scale, and the turning of the gear thereby will put a gradually-increasing tension upon the armature-spring, which will nally exert suicient force to cause the armature to let go and fly away from the magnet, the indicator appearing at the opening in the face and the needle at the moment of appearance showing upon the scale the number of amperes of current passing in the circuit at the time of release ot' the armature. Upon seeing the indicating-disk at the opening the observer immediately ceases turning the knob and the needle will remain at the reading it gave upon the separation of the armature from the magnet, it being held against displacement from the movement and shock of contact of the armature with the stop by the pressure of the spring-finger upon the gear. The current through the resistance ot' the two coils in series (ten ohms) having been secured, giving a reading which may be called C1, the fingerpiece of the switch is pressed, bringing the spring member thereof against the stationary contact-piece and short-circuiting the resistance-coil. The current then passes through the conductor 32', the members of the cut-out, and the conductor 38 to the binding-post 32. This gives an increased current reading through the resistance of the magnet coil alone, (five ohms,) which may be called C2, secured in the same way as was the previous reading. Then the external resistances ofthe circuit, ten and five ohms, respectively, and these .two current values C1 and C2 being known and calling the unknown electromotive force of the battery E and its unknown internal resistance R and substituting these values and characters in the well-known expression ot' Ohms law, E=OR, two equations will result:

113:01 (R4-l0) and EIC2 (R4-5).

As E is the same in both cases, the second member of each equation may be formed into the equation C1 (R-|-1O)=(J2 (R4-5). 'Dividing and transposing,

which, upon substituting the known values of the current strength and reducing, will give the internal resistance ofthe battery in ohms. Substituting the above value of R in one of the equations for E and reducing gives IOO IIO

plied to the measurement of any source of electrical energy which will give current strength Within its capacity.

Having thus described my invention, I claim- 1. The combination,with a case or support, of a graduated scale; a needle or pointer adapted to move over said scale; an electromagnet carried by the case; an armature for said electromagnet flexibly attached to the needle; means for simultaneously moving the needle and putting tension upon the armature attachment; and a brake or retainer coacting with said means.

2. The combination, with a case or support, of a graduated scale; a needle or pointer adapted to move over said scale; an electromagnet carried by the case; an armature for said electromagnet flexibly attached to the needle; means for simultaneously moving the needle and putting tension upon the armature attachment; and an adjustable brake or retainer coacting with said means.

3. The combination,with a case or support, of a graduated scale; a needle or pointer adapted to move over said scale; an electromagnet carried by the case; an armature for said electromagnet iiexibly attached to the needle; and an indicator movable with the armature.

4. The combination with a case or support, of a graduated scale; a needle or pointer adapted to move over said scale; an electromagnet carried by the case; an armature for said electromagnet flexibly attached to the needle; and a resistance also carried by the case and capable of being put into or cut out of the electromagnet-cirenit.

5. The combinatiomwith a case or support, of a graduated scale; a needle or pointer adapted to move over said scale secured to a pivot; an electromagnet carried by the case; a spring connected 'to the pivot; an armature for the electromagnet attached to the spring and an indicator attached to the armature.

6. The combination with a case or support, of a graduated scale; a needle or pointer adapted to move over said scale secured to a pivot; an electromagnet` carried by the case; a spring connected to the pivot; an armature for the electromagnet attached to the spring; a finger-piece, and intermeshing gears carried by the finger-piece and pivot.

7. The combination,with a case or support, of a graduated scale; a needle or pointer adapted to move over said graduated scale secured to a pivot; an electromagnet carried by the case; a spring connected to the pivot; an armature for the electromagnet attached to the spring; a finger-piece geared to the pivot; and a brake or retainer coacting with the gearing.

8. rIhe combination with a case or support, of a graduated scale; a' needle or pointer adapted to move over said scale secured to a pivot; an electromagnet carried by the case; a spring connected to the pivot; an armature for the electromagnet attached to the spring; a finger-piece geared to the pivot; and means for limiting the movement of the gearing.

9. The combination,with a case or support, of a graduated scale; a needle or pointer adapted to move over said scale secured to a pivot; an electromagnet carried by the case; a spring connected to the pivot; an armature for the electromagnet attached to the spring; a spring-brake coacting with the gearing; and means for varying the pressure of said brake.

10. The combination, with a case or support, of a face or d ial carried thereby provided with an opening; a needle or pointer adapted to move over the face; an electrolmagnet supported at the rear of said face;

an armature therefor and an indicator attached to the armature and adapted to appear at the opening in certain positions of the armature.

11. The combination, of a case or support, of a face or dial carried thereby provided with an opening; a needle or pointer adapted to movehover the face; an electromagnet supported at the rear of said face; an armature therefor, an indicator attached to the armature and adapted to appear at the opening in certain positions of the armature; and a stop for the armature in proximity to the opening.

12. The combination, with an inclosed case adapted to be carried in the pocket provided externally with two connectors or bindingposts and a rotary finger-piece, of a face or dial carried by the case; an electromagnet and a resistance in the case in circuit with the connectors; a needle or pointer movable over the face; and an armature for the electromagnet; both needle and armature being geared to the rotary iinger-piece.

13. The combination, with an inclosed case adapted to be carried in the pocket and provided externally with two connectors or binding-posts, a rotary linger-piece and a fingerpiece to actuate a switch or cut-out; of a face or dial carried by the case an electromagnet; a resistance and a switch or cut-out in the case in circuit with the connectors; a needle or pointer movable over the face; and an armature for the electromagnet, both needle andarmature being geared to the rotary nger-piece.

14. The combination, with an inclosed case adapted to be carried in the pocket and provided externally with two connectors or binding-posts, a rotary finger-piece and a fingerpiece to actuate a switch or cut-out; of a face or dial carried by the case; an electromagnet, a resistance and a switch or cut-out in the case in circuit with the connectors; a needle or pointer movable over the face; and a ilexibly-mounted armature for the electromagnet; both needle and armature being geared to the rotary linger-piece. y

CHARLES R. UN DERHILL.

Witnesses:

JAMES A. MisHooD, ALFRED HOWELL.

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